The present invention relates to a recording method and a recording apparatus for a write once type optical disc in which recording can be performed once in an unrecorded area but the written data cannot be erased for rewrite.
Conventionally, a high-density, a large-capacity reproduction-dedicated optical disc has been developed. Especially, a DVD-ROM (Digital Versatile Disc-Read Only Memory) disc containing video/audio data is widely spread since it can reproduce a high-quality video by an inexpensive reproduction-dedicated DVD player.
On the other hand, recently, there has been developed a write once type optical disc in which data can be written once but the data written cannot be rewritten such as a DVD-R (DVD-Recordable) and as a device for recording data on the write once type optical disc, a video recorder and a video camera are available on market. On this write once type optical disc, data can be additionally written at a time interval and after finalization to complete additional writing, the disc becomes a reproduction-dedicated disc which cannot perform recording any more. Moreover, by recording video data in the DVD video format, it is possible to perform reproduction by a reproduction-dedicated DVD player.
In order to reproduce the write once type optical disc by the DVD player, the final data and the data structure should be in the state compatible with a reproduction-dedicated optical disc. However, the write once type optical disc has a record management area for managing the disc record state at a portion other than the data structure of the reproduction-dedicated optical disc, for example, in the inner circumferential side. That is, in the state before finalization processing when additional write can be performed, the disc record state such as the user data record position is successively recorded in the record management area and when performing the finalization processing, the data is used to create data of the Lead-in area and the Lead-out area, so as to have the same data and data structure as the reproduction-dedicated optical disc, thereby assuring the compatibility.
Hereinafter, the configuration will be detailed further with reference to the drawings. FIG. 2 shows an area structure of a write once type optical disc.
The area of the disc is divided into a disc record management area 201, a Lead-in area 202, a user data record area 203, and a Lead-out area in this order from the innermost circumferential side. In the disc record management area 201, there is successively recorded disc record management information including the position information indicating the reference of the final address of the user data recorded and the disc record information such as record-in-process state and the finalization complete state. Moreover, in the Lead-in area 202 and the Lead-out area 204, disc access information for accessing the disc after the finalization processing is recorded. The disc access information includes a disc record capacity after the finalization processing.
Moreover, in this example, the user data record area 203 is divided into a file system area 205, a video/audio management information area 206, and a video/audio record area 207 in this order from the side of the Lead-in area 202. In the file system area 205, each file position information on the file as a set of video/audio after the finalization processing is recorded. In the video/audio management area 206, management data for managing the video/audio data is successively recorded. The management data includes indefinite video/audio data before performing finalization processing and definite video/audio management data after the finalization processing is performed. In the video/audio record area 207, video/audio data compressed by the MPEG (Moving Picture Experts Group) method is successively recorded.
It should be noted that a trial write area for acquiring the recording power exists in the inner side of the disc record management area 201. However, its explanation is omitted here.
Moreover, among the areas of the write once type optical disc, the disc record management area 201 does not exist in the reproduction-dedicated optical disc. The other areas have the same area structure as in the reproduction-dedicated optical disc and can be used as the reproduction-dedicated disc after the finalization.
In each of the areas of the write once type optical disc, data which has been written cannot be erased to be rewritten. Accordingly, at the stage while user data is additionally recorded on such a disc, the file position information on each file recorded and the final disc recording capacity are not determined. For this, no recording is performed at a part of the Lead-in area 202, the Lead-out area 204, the file system area 205, and part of the video/audio management information area 206 where information for final definition upon finalization is recorded and the disc record management information including the record position information on each area of the user data record area 203 is recorded on the disc record management area 201.
When the power supply to the video/audio recording/reproduction device is turned on or when a disc is inserted, the head position of the unrecorded portion is searched according to the position information indicating the reference of the final address recorded on the disc record management area 201. Here, if the position information recorded on the disc record management area 201 is not newest, unused record positions in the file system area 205, the video/audio management information area 206, and the video/audio record area 207 are searched. During this search, no recording or reproduction can be performed. Accordingly, it is preferable that the newest position information be recorded on the disc record management area 201 upon each recording. However, in the disc record management area 201 also, data which has been written cannot be erased to be rewritten and the area size is limited, which in turn limits the number of additional recording times. Consequently, it is general that the newest information is not recorded for each recording.
For example, if the newest disc record management information is recorded on the disc record management area 201 for each one recording, the disc record management information cannot be updated after recording is performed a predetermined number of times. Especially in the case of a video camera in which a plenty of small video/audio data are recorded, there is a problem that the disc record management information cannot be updated. Moreover, it is possible to limit the recording maximum capacity of the user data record area 203 by the limit for the number of recording times of the disc record management information, but this disabled effective use of the disc capacity. Furthermore, during finalization, in order to inhibit additional write onto the disc any further, the disc record management information is recorded as finalized on the disc record management area 201. That is, an unused area should remain in the record management area 201 even during finalization.
In the conventional technique concerning this problem, the file management information is stored in a memory and according to data write, the file management information in the memory is updated to the newest, so that when power is turned off or the disc (recording medium) is taken out, the file management information updated in the memory is recorded on the disc so as to reduce the number of additional writes of the file management information (see JP-A-2002-238015).